1. Field of the Invention.
This invention relates to a solar heat collector having a breather tube.
2. Discussion of the Technical Problems.
The advantages of solar heat collectors to collect solar energy for subsequent use have been recognized in the prior art. For example, in U.S. Pat. No. 2,462,952, there is taught the use of solar energy to activate a desiccant material used to absorb moisture from an enclosure. In general, a receptacle is filled with desiccant material and mounted on the upper portion of the enclosure. Communication is provided (1) between the interior of the enclosure and the desiccant material and (2) between the atmosphere and the desiccant material. The outer surface of the receptacle and the enclosure are heated by solar energy to heat the desiccant material and expand the air in the enclosure. The expanded air moves from the enclosure through the desiccant material and into the atmosphere to dehumidify the enclosure. The heating of the desiccant material by solar energy and the movement of air therethrough activates the desiccant material.
The solar heat collector of the above-identified patent has drawbacks. More particularly, a portion of the absorbed solar energy is lost due to conduction and/or convection heat losses to the atmosphere.
In U.S. Pat. application Ser. No. 450,703 filed on Mar. 13, 1974, in the name of Pandit G. Patil and entitled "Solar Heat Collector Window" there is taught a solar heat collector that reduces conduction and/or convection heat losses to the atmosphere by providing an outer cover plate, an intermediate cover plate, a solar radiation absorber and a spacer assembly. The spacer assembly (1) maintains the outer cover plate, intermediate cover plate and absorber in spaced relationship to provide airspaces therebetween; (2) removes moisture from the airspaces between the cover plates and absorber; and (3) prevents moisture from entering the airspace between the cover plates and the absorber. The cover plates reduce heat losses to the atmosphere and the spacer assemblies maintain the air in the airspaces free of moisture.
Although the solar heat collector taught in the abovementioned U.S. Pat. application is ideally suitable for collecting solar radiation for subsequent use, the solar heat collector has limitations. For example, during use, the absorber absorbs solar radiation and is heated. The airspace between the adjacent cover plate and the absorber is heated by convection and/or conduction. As the air in the airspace is heated, it expands in volume, exerting pressure to move the absorber and the cover plates away from each other. As can be appreciated, during extremely hot days the pressure of expanded air in the airspace may be of sufficient magnitude to cause a break in the spacer assemblies allowing moisture to enter the airspaces. The moisture in the airspaces condenses on the cover plates and absorber reducing the transmittance coefficient of the cover plates, reducing the absorptivity coefficient of the absorber and/or increasing the emissivity coefficient of the absorber.
It would be advantageous therefore if a solar heat collector was available that did not have the limitations of the prior art heat collectors. More particularly, a solar heat collector having a breather tube to compensate for air pressure changes within the collector while keeping moisture from entering the airspace.